It seems that in our day and age humans rely on caffeine for many things from that morning cup of coffee, soda with popcorn, caffeine infused skin products and many other applications. Our premises are that if caffeine can help with our skin and energy boost then wouldn’t the same apply to plants? The goal of this biology project is to examine the effect of caffeine on plant growth. Caffeine comes from a plant so it would seem that it could help plant growth. A plausible prediction is caffeine will support plant growth by providing a source of nitrogen or carbon dioxide through its the catabolic breakdown.
Could the use of caffeine aid in accelerating and benefit the plant growth? Method To test our hypothesis, we set up an experiment where we observed the effect that caffeine has on plant growth. In the experiment, the dependent variables were our measurements and observations of the health and growth of the plants. Also, we conducted some observations of each plant’s cells under a microscope to observe any changes. We included the observation and stained slide analysis of the roots of each plant as well. The independent variable was the different concentrations of caffeine given to the plants.
The amount of water, light exposure, soil type, plant type and caffeine type were the most important control variables. There were three different asparagus bean plants used. First, we began with 3 asparagus plants with the same amount of leaves, height, and age. Next, we introduced caffeine to the 2 of our plants, the third was a control and received no caffeine. The concentrations of caffeine were 2. 5 mL, 5 mL, and the control plant had no caffeine only water. Each plant was given 100 mL of their perspective fluid 3-4 times per week. The conditions for all the plants were the same otherwise.
We then observed and evaluated the effects of caffeine on the experimental plants in comparison to the control plants that was not exposed to caffeine. We measured the plant’s height by measuring from the top of the soil up to the apical bud. Pictures of each plant were taken at set intervals of time to show effect of caffeine on plants visually (Figure 1). Our data was recorded both in quantitative and qualitative observations. We measured the plants everyday (possible) that we were in the lab, which ended up being for a period of four weeks.
The quantitative observations were height measured in inches and is portrayed in the included data (Figure 2). The overall health of the plants that received treatment appeared marginally more deteriorated: stems appear a diminutive in proportion to the control plant. The petioles of the higher concentrations seem shorter. Each plant was removed from its soil and root structure was observed. Upon observation of the roots we noticed a substantial difference in the health as well as the fact that the roots of the plants receiving caffeine. The caffeinated plant roots were markedly smaller and thinner than that of the control plant.
A sample of each of the plant roots was obtained from both the uppermost root to the tip for scrutiny under a microscope. The slides were stained prior to observation. The objective was to view cellular structure and see if any significant differences could be seen. On all three slide we were unable to see any cellular differences or damages. We were unable to proceed further, as more sensitive equipment would have been required and was not available. Discussion In the experiment we noticed that the plants receiving the caffeine treatments tended to have skinnier less healthy appearing stems.
They also appeared to have shorter petioles and slight yellowing of the leaves, especially the higher concentrations. All of the other treatments grew at around the same height and had very minimal health detriment. These results appeared random and seemed to have no type of correlation, other than the fact that they were all shorter than the control plants (Figure 1). A speculation of the yellowing in older leaves was a possible deficiency of nitrogen due to the inability to catabolize the caffeine into ammonia (further broken down into nitrogen).
While performing our procedures we experienced a couple experimental errors that were very important. The first major error was our inability to maintain daily watering consistently as a control variable. We watered the plants unevenly and also did not supply all of the plants with enough water to last the entire weekend. This could account for the plants that experienced diminished health. Secondly, our study should have included a much broader scope of plants as well as a large quantity of plants in each group for a more accurate collection of data.
Lastly, the caffeine treated plants should have had several different ranges of concentrations as opposed to only the two. Because of our experimental errors, the results are inconclusive and do not provide definitive proof towards the reasoning behind our failed hypothesis. The following is a deduction. If the health problems, we observed were from our watering error, could the plants have broken down the caffeine? However, if the health problems were a result of the caffeine rather than dehydration, then our hypothesis was indeed incorrect because the plant did in fact absorb the caffeine and it caused detriment rather than growth.
Because there is no discernable pattern in plant cell structure of function with respect to caffeine concentration along with our experimental errors, we concluded that our hypothesis is incorrect. If we were given the opportunity to redo the experiment, we would like to water our plants regularly so that the plants would not dry out, which may have affected our results. An additional aspect we would like to attempt is having a caffeine-producing plant as one of the controls in order to see how additional caffeine affects a plant that we readily know can catabolize caffeine.